The K Prize - 100% reusable spaceplane to orbit and back

[Stochasty]

I posted a link to the Mun trip above, but I wanted to show off my new ship a little more, so I'm making a gallery of her exploits.

Update: Added the third through sixth trips.

First trip: Single Stage to the Mun, Twice!

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Second trip: Picking up Jeb in Eve orbit, then stopping by Gilly and Minmus on the way back to Kerbin.

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Trip three: To Duna and Ike with Jeb and Bill!

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Trip four: To Dres!

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Fifth trip: A simultaneous mission to Laythe and Vall.

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Sixth trip: To Eeloo1

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Planned future trips: Moho! (What can I say; it's the only thing left I haven't gotten to, save Tylo and Eve which are impossible. Moho will be hard, though; I can save some delta-v using an Eve assist but it will take some serious planning to have a hope of getting there and coming home.)

Edited August 14, 2013 by Stochasty

[drewscriver]

I don't think it's going to win prizes in any given category, but I wanted to share my most successful SSTO so far, the Chalice Mk4

Here, it lofted approximately 7 tons into LKO, and returned safely to KSP. Stable flight the whole way, though I did transfer all the remaining fuel into the forward tanks before re-entry, which was a bit tedious. I'm reworking the design a bit in Mk5, to hopefully stop the COM shifting so much between full and empty.

Anyhow, I hope you enjoy the pictures.

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[pa1983]

Dont realy know if you can "win". Can get a lot of distinctions but so can every one if they want to go for that. Make something YOU like and it will be fine. I like your craft it seems capable with the part it has.

CoG is easy to solve by having the fuel tanks in parallel but IF I have fuel tanks fare ahead or above CoG I drain those first during the 45 degree climb up till 16km or so and make sure CoG is where you want it after that.

Just a mater of plumbing. I did a concord style SSTO like that with the jets at 5 degree angle and the rockets at 10 degrees then I had the rocket fuel and some jet fuel with the engines in the engine nacelles like the concord but I also had 3 fuel tanks in the fuselage above CoG but I had just enough so they where drained first before I got so high the control surfaces would not have been able to compensate so by the time they where emtpy CoG was in Line with CoT.

[ThePsuedoMonkey]

My personal best is the Iron Buzzard, an 18T lifter. I don't plan on building anything bigger due to part counts though.

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Grab the whole series here.

Her launch mass is 66.82T, of which 28.8T are propellants. That puts her payload fraction at 26.9% with a propellant to payload ratio of 1.60. The four jets are fed by 8 ram intakes and 16 radial scoops. The biggest issue is fighting the lift during descent, but there is a drogue on the abort group in case you lose that battle. I tried to make the fuselage look a little more aerodynamic, but that ended up adding too much mass to it

[Crowella]

So I've had a crack at a 100% reusable space plane. Mind, with a little intake abuse which I'll likely modify in the future by putting intakes under the wings on separate fueslages rather than clumped together.

Using it at the moment to construct a space station in LKO section by section. It can carry AND land with a 4.5 tonne payload. No requirement to transfer fuel between tanks or anything like that. Simple take off and go. Very easy to control. Normally landing the craft by gliding now over controlled flight.

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Edited August 12, 2013 by Crowella

[drewscriver]

Dont realy know if you can "win". Can get a lot of distinctions but so can every one if they want to go for that. Make something YOU like and it will be fine. I like your craft it seems capable with the part it has.

Thanks for the advice on COG matters, and I'm glad you like the Chalice. I'll admit I enjoy it as much for the aesthetics as the practicality. I could probably make better performing craft, but I stick to a few self-imposed rules, such as 1 intake per fuselage section. As it is, I actually think it could've pulled off a 10T load if I was a better pilot.

The next version I'm looking to shift the engine mass forward so that fuel burn has less of an impact, though I'm afraid the mk5 still has some teething issues...

Perhaps more struts?

[numerobis]

One thing about moving engine mass forward is that you lose the control authority the engine gimbals provide at high altitude.

(Though you may ask yourself: what jet engine gimbals in real life?)

[drewscriver]

One thing about moving engine mass forward is that you lose the control authority the engine gimbals provide at high altitude.

Crud. I hadn't thought of that.

Oh well, this is KSP, so I'll finish the design and see what happens. There's always mk6, after all...

[Psycix]

(Though you may ask yourself: what jet engine gimbals in real life?)

The engine doesn't gimbal, just the nozzle.

It's used in a lot of modern jet fighters for extra maneuverability.

A few links to thrust vectoring jet engines:

http://en.wikipedia.org/wiki/Pratt_%26_Whitney_F119

http://en.wikipedia.org/wiki/File:Sukhoi_Su-35S_07_RED_PAS_2013_07.jpg

http://en.wikipedia.org/wiki/File:Iris_vectoring_nozzle.jpg

[Stochasty]

One thing about moving engine mass forward is that you lose the control authority the engine gimbals provide at high altitude.

Unless you move them far enough forward. My current craft has a rear-mounted LV-N counterbalanced by two forward-mounted turbojets, and the gimbal on the jets effectively acts as a second set of canards. (Well; unless KSP has gimballing messed up on forward mounted engines; I've got enough control authority, so I just assumed that they were working as intended.)

[pa1983]

Well having engines fare back has a big problem. There very heavy in comparison to a lot of other parts in the game. So its hard making a "real" plane sens real jet engines are longer moving CG not as fare back.

The main reason I still use a maned pod is because it works as a counter wight for the engines.

My latest craft also has 1/3 of the jets in the rear but the other 2/3 on the wings closer to CG that way I can use the rear jets during the last part of the ascent with high level of control.

For smaller crafts a single jet in the rear is a good trade off and offers safety from flame out.

Also having engines fare back and lots of wings forward seems to create a craft with the same effect as a front stabilizer. They are itinerantly unstable but responsive. Most modern fighters uses this to its advantage with fly by wire systems but KSP has nothing like it and its aerodynamic model and current control systems seem unable to deal with it.

Building something like the concord in KSP often has the problem that the pitch surfaces side by side with the ailerons wont provide enough force to rotate on the runway.

[numerobis]

Unless you move them far enough forward. My current craft has a rear-mounted LV-N counterbalanced by two forward-mounted turbojets, and the gimbal on the jets effectively acts as a second set of canards. (Well; unless KSP has gimballing messed up on forward mounted engines; I've got enough control authority, so I just assumed that they were working as intended.)

KSP engines gimbal as if they were mounted on the back, even if you mount them on the front. If you mount engines up front, and you turn off the reaction wheels, and don't have control surfaces, you will see that pushing w pushes the nose down, whereas pushing d pushes the nose left.

[Stochasty]

KSP engines gimbal as if they were mounted on the back, even if you mount them on the front. If you mount engines up front, and you turn off the reaction wheels, and don't have control surfaces, you will see that pushing w pushes the nose down, whereas pushing d pushes the nose left.

Huh. I learned something new. So forward mounted gimballing engines are counter productive; I'll have to remember to turn gimballing off for them in the future (not that it matters much with this particular craft).

[Karmacoma]

Well thought i'd have a go at this being as i have been making a few SSTO's recently. So i threw mechjeb out the window and brushed up my piloting skills using "The Styx"

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made it to 100Km circularised orbit, then back to Kerbin and safely onto the runway

I haven't flown without using mechjeb in quite a while due to excessive laziness so it was nice to prove to myself i could still fly and that the craft worked and flew very easily!

Apologies for the dark pics both take off and landing were at night my timing is great!

Link to .craft ↓ down there in my sig

Edited August 14, 2013 by Karmacoma

[Stochasty]

This should properly go in my gallery post up thread, but considering it's my magnum opus I wanted to make a new post to show it off.

Behold, a single stage mission to Eeloo:

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This is in addition to the trips to Dres, Vall, and Laythe I linked in my gallery post. In all honesty, the mission to Dres was actually harder; I had something over 3km/s delta-v left in the tank when I began burning for home from Eeloo, and I could have made it using only a few hundred if I were willing to wait on a good geometry with Jool. Instead, I came home Jeb-style: a sundive, intercepting Kerbin at over 10km/s.

With this mission, there are now only three places in the solar system I have not managed a single stage return from: Moho, Tylo, and Eve. Eve is impossible, and Tylo probably so. I have my sights set on Moho, though: I will find a way.

[pa1983]

Poor Kerbals getting fried like that

[Stochasty]

I blame Jeb. It was entirely his fault, and had nothing whatsoever to do with the sheer boredom of having to wait over an hour for the right geometry.

[ihtoit]

Craft files would be nice by the end of this challenge. Making space planes is hard! making SSTO space plane is extra hard.

Can\'t wait to see what people come up with...

Challenge accepted.

My standard SSTO scout plane. No removable parts, in-flight refuel capable, and capable of single-tank flights from the runway standing start to Mun, tail landing, and back to a runway landing.

[ihtoit]

Woah! My biggest SSTO is 80 tons! that's big!

psssh, amateurs...

(my record stands at 862 tons, it burned off 210 of that just making orbit. No side boosters, it's a pure single stage)

[ihtoit]

OK, moderators, are you SEEING this!?

I vote the prize for the most awesome inspired design goes to this guy.

(can you post the craft file??)

[ihtoit]

One thing about moving engine mass forward is that you lose the control authority the engine gimbals provide at high altitude.

(Though you may ask yourself: what jet engine gimbals in real life?)

There's the Lockheed Martin F-35 Lightning II, which engine has a full gimbal range of 110 degrees (it also has a ducted electric fan just behind the cockpit), allowing it to perform a fully loaded and fueled VTOL off a rolling carrier deck. Oh yeah, and it can go from hover at 30ft to Mach 1.21 supercruise at 21,000 feet in 44 seconds.

[boolybooly]

Thanks all for your contributions, I have been updating the OP, and offer my congratulations to the K Prize winners for completing the challenge.

Thanks for your screeny ihtoit, effective looking design though I cant work out what I am seeing at the wing base!? Is it all stock (tanks wings and engines)? Also are you saying it has completed a K Prize mission, ie orbit and return without refuelling in accord with the rules in the OP? Your word is good enough, its just the description you gave wasnt specific. I am trying to work out whether to link it in the roll of honour or as a gate crasher!

[sanderlebau]

There's the Lockheed Martin F-35 Lightning II, which engine has a full gimbal range of 110 degrees (it also has a ducted electric fan just behind the cockpit), allowing it to perform a fully loaded and fueled VTOL off a rolling carrier deck. Oh yeah, and it can go from hover at 30ft to Mach 1.21 supercruise at 21,000 feet in 44 seconds.

That is if it actually worked.

[BeTa77]

I finally moved away from that tried and true designed I used to use, and went smaller.

The Featherweight I is designed to go up to 80km, though I suspect it can go higher. Pics follow.

Launch Config:

Coasting to Apokee:

Proof of orbit: (clouds are fromm universe replacer)

Some orbital pictures, with clouds and skybox from Universe Replacer:

Coming in hot:

Final approach:

Alive and ready for a refuel:

[glacierre]

Thanks for your screeny ihtoit, effective looking design though I cant work out what I am seeing at the wing base!? Is it all stock (tanks wings and engines)? Also are you saying it has completed a K Prize mission, ie orbit and return without refuelling in accord with the rules in the OP? Your word is good enough, its just the description you gave wasnt specific. I am trying to work out whether to link it in the roll of honour or as a gate crasher!

I would need more than just word to believe that that is stock AND can make orbit by itself. I remember a purely nuclear SSTO by Stochasty some time ago and it needed way more tanks and lift than just that. (And since I don't see a single air intake...)